Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: quantos membros da tripulação tinham u15 3rd iv sendo bgs e u15 1st iv sendo acgs e open 1st viii sendo acgs
 ###Tabelas: CREATE TABLE turkish_cd_track_listings (turkish_cd_track_listings_id AUTO_INCREMENT PRIMARY KEY, Track INT, Title VARCHAR, Songwriter(s) VARCHAR, Producer(s) VARCHAR, Length VARCHAR) CREATE TABLE completed (completed_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Height of bridge structure VARCHAR, Longest Span VARCHAR, Type VARCHAR, Opened INT, Location VARCHAR) CREATE TABLE winning_head_of_the_river_championship_events (winning_head_of_the_river_championship_events_id AUTO_INCREMENT PRIMARY KEY, Crew INT, Open 1st VIII VARCHAR, Open 2nd VIII VARCHAR, Open 3rd VIII VARCHAR, U16 1st VIII VARCHAR, U16 2nd VIII VARCHAR, U16 3rd VIII VARCHAR, U15 1st IV VARCHAR, U15 2nd IV VARCHAR, U15 3rd IV VARCHAR, U15 4th IV VARCHAR, U15 5th IV VARCHAR, U15 6th IV VARCHAR) CREATE TABLE top_assister (top_assister_id AUTO_INCREMENT PRIMARY KEY, P INT, Player VARCHAR, Position VARCHAR, League INT, Copa del Rey INT, Champions League INT, Total INT) CREATE TABLE swimming_and_diving (swimming_and_diving_id AUTO_INCREMENT PRIMARY KEY, Combined VARCHAR, 50 yard Freestyle VARCHAR, 100 yard Freestyle VARCHAR, 200 yard Freestyle VARCHAR, 500 yard Freestyle VARCHAR, 100 yard Backstroke VARCHAR, 100 yard Butterfly VARCHAR)  
SELECT COUNT Crew FROM winning_head_of_the_river_championship_events WHERE U15 3rd IV = BGS AND U15 1st IV = ACGS AND Open 1st VIII = ACGS